package com.itheima.reggie.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.reggie.common.BaseContext;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 * 注意，需要在Application类加上@ServletComponentScan注解，才会扫描到@WebFilter注解
 */
@Slf4j
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        // 1. 获取本次请求的uri
        String requestUri = request.getRequestURI();
        log.info("拦截到请求：{}", requestUri);

        // 定义不需要处理的请求路径
        String [] urls = new String[] {
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**"
        };

        // 2.判断本次请求是否需要处理，如果不需要处理，则直接放行
        if (check(urls, requestUri)) {
            log.info("本次请求{}不需要处理", requestUri);
            filterChain.doFilter(request, response);
            return;
        }

        // 3.判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("用户id为：{}", request.getSession().getAttribute("employee"));
            BaseContext.setCurrentId((Long) request.getSession().getAttribute("employee"));
            filterChain.doFilter(request, response);
            return;
        }

        log.info("用户未登录，需要登录");
        // 4.如果未登录，则返回未登录结果，通过输出流方式向客户端页面响应数据
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }

    /**
     * 路径匹配，检查
     * @param urls
     * @param requestUri
     * @return
     */
    public boolean check(String [] urls, String requestUri) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestUri);
            if (match) {
                return true;
            }
        }
        return false;
    }
}
